/*
 * RentalReturnDAO.java
 *
 * Created on March 26, 2007, 10:53 PM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */
 
package edu.byu.isys413.jjenkins.data;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;

/**
 * This class contains methods to create, read, update and delete the
 * Physical Object. It also contains methods to read an object by
 * serveral different criteria. All interaction between the object
 * and the database is done through this class.
 *
 * @author      Josh
 * @version     1.0
 *
 */
public class RentalReturnDAO {
    
    private static RentalReturnDAO instance = null;
    
    /** Creates a new instance of RentalReturnDAO */
    private RentalReturnDAO() {
    }
    
    /** This method implements the singleton pattern. It insures that only
     * on instance of RentalReturnDAO exists
     *
     * @return: RentalReturnDAO instance */
    
    public static synchronized RentalReturnDAO getInstance() {
        if (instance == null) {
            instance = new RentalReturnDAO();
        }
        return instance;
    }
    
    /** This method creates a new RentalReturnBO with a unique QUID, puts the interest
     * in cache, and then returns it to the calling method.
     *
     * @return: RentalReturnBO
     * @throws: DataException
     */
    
    public RentalReturnBO create() throws DataException {
        try {
            
            String id = GUID.generate();
            RentalReturnBO object = new RentalReturnBO();
            object.setId(id);
            Cache.getInstance().put(object.getId(), object);
            return object;
        } catch (Exception e) {
            throw new DataException("Could not create GUID", e);
        }
        
    }
    
    
    /**
     * This is the public read statement.  It loads an existing record
     * from the database.
     *
     * @Par: String: id
     * @Return: RentalReturnBO
     * @Throws: DataException
     */
    public synchronized RentalReturnBO read(String id) throws DataException {
        
        // Checks to see if the item is in cache
        Cache cache = Cache.getInstance();
        RentalReturnBO object = (RentalReturnBO)cache.get(id);
        try {
            
            // Gets connection
            ConnectionPool connPool = ConnectionPool.getInstance();
            Connection conn = connPool.get();
            
            // If the item is not in cache a connection is checked out and
            // The item is read from the database.
            if(object == null){
                try {
                    //reads in object
                    object = read(id, conn);
                    
                }catch (SQLException e) {
                    conn.rollback();
                    throw new DataException("Could not retrieve record for id=" + id, e);
                }
            }
            
            // connection committs and is returned.
            conn.commit();
            connPool.release(conn);
            
            
            
        } catch (SQLException e) {
            throw new DataException("Could not retrieve record for id=" + id, e);
        } catch (DataException e) {
            throw new DataException("Could not retrieve record for id=" + id, e);
        } catch (ConnectionPoolException e) {
            throw new DataException("Could not retrieve record for id=" + id, e);
        }
        
        // Return object
        return object;
    }
    
    /**
     *  This is a package method that is called by the public read (above) or
     *  by another DAO.  Either way we already have a connection to the database
     *  to use.  The user (controller) code never calls this one directly, since
     *  it can't know about Connection objects or SQLExceptions.
     *
     *  @Par: String: id, Connection conn
     *  @Return: RentalReturnBO
     *  @throws: DataException, SQLException
     */
    synchronized RentalReturnBO read(String id, Connection conn) throws SQLException, DataException {
        
        
        // Checks to see if the item is in cache
        Cache cache = Cache.getInstance();
        RentalReturnBO object = (RentalReturnBO)cache.get(id);
        
        // Quieries that database
        if(object == null){
            
            PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM rental_return WHERE rental_return_id = ?");
            pstmt.setString(1, id);
            pstmt.execute();
            ResultSet rs = pstmt.getResultSet();
            
            if (rs.next()) {
                object = new RentalReturnBO();
                object.setId(rs.getString("rental_return_id"));
                object.setDateIn(rs.getDate("date_in"));
                object.setRental((RentalBO)RentalDAO.getInstance().read(rs.getString("revenue_source_id")));
                
                // Sets already in database
                object.setObjectAlreadyInDB(true);
                
                // adds to cache
                cache.put(object.getId(), object);
                
            }else{
                throw new DataException("Object was not found in the database.");
            }
        }
        
        
        // returns object
        return object;
    }
    
    /**
     * This is the public save method.  It is what is called when
     * the user (controller) code wants to save or update an object
     * into the database.
     *
     * @par RentalReturnBO object
     * @throws DataExcpetion
     */
    public synchronized void save(RentalReturnBO object) throws DataException {
        try {
            
            
            // retrieve a database connection from the pool
            ConnectionPool connPool = ConnectionPool.getInstance();
            
            Connection conn = connPool.get();
            
            
            try {
                
                // Saves Interest
                save(object, conn);
                
            }catch (SQLException e) {
                conn.rollback();
                throw new DataException("Could not save record for" + object.getId(), e);
            }
            
            // connection committs and is returned.
            conn.commit();
            connPool.release(conn);
            
            // touch the cache for the object
            Cache.getInstance().touch(object.getId());
            
            
            
        } catch (DataException e) {
            throw new DataException("Could not save record for" + object.getId(), e);
        } catch (ConnectionPoolException e) {
            throw new DataException("Could not save record for" + object.getId(), e);
        } catch (SQLException e) {
            throw new DataException("Could not save record for" + object.getId(), e);
        }
        
        
    }
    
    /**
     *  This is a package method that is called by the public save (above) or
     *  by another DAO.  Either way we already have a connection to the database
     *  to use.  The user (controller) code never calls this one directly, since
     *  it can't know about Connection objects or SQLExceptions.
     *
     *  By having other DAOs call this save method (rather than update or
     *  insert below, each DAO in a chained save (like the CustomerDAO calling
     *  MembershipDAO calling InterestDAO save chain) can independently decide
     *  whether to udpate or insert the BO it's saving.  That's why I made
     *  update and insert private rather than package level -- if you call
     *  them directly from another DAO, this DAO can't decide whether it's
     *  object needs to be inserted or updated.
     *
     *  @par: RentalReturnBO, Connection
     *  @throws: SQLException, DataException
     */
    synchronized void save(RentalReturnBO object, Connection conn) throws SQLException, DataException {
        
        // check the dirty flag in the object.  if it is dirty,
        // run update or insert
        if (object.isDirty()) {
            if (object.isObjectAlreadyInDB()) {
                this.update((RentalReturnBO)object, conn);
            }else{
                this.insert((RentalReturnBO)object, conn);
            }
            object.setDirty(false);
        }
        
        
        
    }
    
    /**
     * This method is really a part of save(bo, conn) above.  It could be
     * embedded directly in it, but I've separated it into it's own method
     * to isolate the SQL udpate statement and make it more readable.  But
     * logically, it's really just a part of save.
     *
     * @Par RentalReturnBO object
     */
    private synchronized void update(RentalReturnBO object, Connection conn) throws SQLException, DataException {
        
        PreparedStatement pstmt = conn.prepareStatement("UPDATE rental_return SET rental_return_id = ?, date_in = ?, revenue_source_id = ? WHERE rental_return_id = ?");
        pstmt.setString(1, object.getId());
        pstmt.setDate(2, object.getDateIn());
        pstmt.setString(3, object.getRental().getId());
        pstmt.setString(4, object.getId());
        
        pstmt.execute();
        
    }
    
    /**
     * This method is really a part of save(bo, conn) above.  It could be
     * embedded directly in it, but I've separated it into it's own method
     * to isolate the SQL insert statement and make it more readable.  But
     * logically, it's really just a part of save.
     *
     * @Par RentalReturnBO object
     */
    private synchronized void insert(RentalReturnBO object, Connection conn) throws SQLException, DataException {
        
        // Creates prepared statemetn
        PreparedStatement pstmt = conn.prepareStatement("INSERT INTO rental_return VALUES(?, ?, ?)");
        pstmt.setString(1, object.getId());
        pstmt.setDate(2, object.getDateIn());
        pstmt.setString(3, object.getRental().getId());
        
        //Executes prepated statement
        pstmt.execute();
        
        //Sets already in database true
        object.setObjectAlreadyInDB(true);
        
    }
    
    
    /** We intentionally do not allow a RentalReturnBO object to be deleted because
     * it could mess up relationships in the database. Obmitting the delete
     * also prevents fraud. */
    
    public synchronized void delete(RentalReturnBO customer)throws DataException{
        throw new DataException("You can not delete a RentalReturnBO");
    }
    
    /**
     *Reads all rentalReturnBOs in the db
     *@return List<RentalReturnBO>
     */
    public synchronized List readAll() throws SQLException, DataException {
        
        List list = new LinkedList();
        
        try {
            
            // Gets connection
            ConnectionPool connPool = ConnectionPool.getInstance();
            Connection conn = connPool.get();
            
            // prepares statemnt
            
            PreparedStatement pstmt = conn.prepareStatement("SELECT rental_return_id FROM physical");
            pstmt.execute();
            ResultSet rs = pstmt.getResultSet();
            
            
            while(rs.next()){
                RentalReturnBO object = new RentalReturnBO();
                object.setId(rs.getString("rental_return_id"));
                object.setDateIn(rs.getDate("date_in"));
                object.setRental((RentalBO)RentalDAO.getInstance().read(rs.getString("revenue_source_id")));
                
                list.add(object);
            }
            
            // connection committs and is returned.
            conn.commit();
            connPool.release(conn);
            
            
            
        } catch (SQLException e) {
            throw new DataException("Could not retrieve record", e);
        } catch (DataException e) {
            throw new DataException("Could not retrieve record", e);
        } catch (ConnectionPoolException e) {
            throw new DataException("Could not retrieve record", e);
        }
        
        
        
        return list;
    }
    
    /**
     * This method queries that database for a list of all physical products in a certain
     * store. It adds these objects to a list and puts them in cache
     *
     *@return: Physical product
     */
    public RentalReturnBO getByRentalID(String rentalID) throws DataException {
        RentalReturnBO object = new RentalReturnBO();
        
        try {
            
            // Gets connection
            ConnectionPool connPool = ConnectionPool.getInstance();
            Connection conn = connPool.get();
            
            // Creates statement and populates list
            try {
                
                // prepares statemnt
                PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM rental_return WHERE revenue_source_id = ?");
                pstmt.setString(1, rentalID);
                pstmt.execute();
                ResultSet rs = pstmt.getResultSet();
                
                //get instance of cache to put objects in
                Cache cache = Cache.getInstance();
                
                if(rs.next()){
                    object.setId(rs.getString("rental_return_id"));
                    object.setDateIn(rs.getDate("date_in"));
                    object.setRental((RentalBO)RentalDAO.getInstance().read(rs.getString("revenue_source_id")));
                    
                    cache.put(object.getId(), object);
                    
                }
            }catch (SQLException e) {
                conn.rollback();
                throw new DataException("Could not retrieve list of objects " + e);
            }
            
            // After all items are read (customer, membership, interest) the
            // connection committs and is returned.
            conn.commit();
            connPool.release(conn);
            
            
            
        } catch (SQLException e) {
            throw new DataException("Could not retrieve list of objects " + e);
        } catch (DataException e) {
            throw new DataException("Could not retrieve list of objects " + e);
        } catch (ConnectionPoolException e) {
            throw new DataException("Could not retrieve list of objects " + e);
        }
        
        // Return object
        return object;
    }
}
